This invention relates to information search and retrieval systems and more particularly to search and retrieval systems which utilize in whole or in part image processing techniques.
As is known in the art, a digital image is an image which may be represented as an array of pixels with each of the pixels represented by a digital word. Often the array is provided as a two-dimensional array of pixels. With the increase in the number of available digital pictures, the need has arisen for more complete and efficient annotation (attaching identifying labels to images) and indexing (accessing specific images from the database) systems. Digital image/video database annotation and indexing services provide users, such as advertisers, news agencies and magazine publishers with the ability to browse through, via queries to an image search system, and retrieve images or video segments from such databases.
As is also known, a content based image retrieval system is an image retrieval system which classifies, detects and retrieves images from digital libraries by utilizing directly the content of the image. Content based image processing systems refer to systems which process information in an image by classifying or otherwise identifying subject matter within the image. Such systems may be used in a variety of applications including, but not limited to, art gallery and museum management, architectural image and design, interior design, remote sensing and management of earth resources, geographic information systems, scientific database management, weather forecasting, retailing, fabric and fashion design, trademark and copyright database management, law enforcement and criminal investigation and picture archiving, communication systems and inspection systems including circuit inspection systems.
Conventional content based image/video retrieval systems utilize images or video frames which have been supplemented with text corresponding to explanatory notes or key words associated with the images. A user retrieves desired images from an image database, for example, by submitting textual queries to the system using one or a combination of these key words. One problem with such systems is that they rely on restricted predefined textual annotations rather than on the content of the still or video images in the database.
Still other systems attempt to retrieve images based on a specified shape. For example, to find images of a fish, such systems would be provided with a specification of a shape of a fish. This specification would then be used to find images of a fish in the database. One problem with this approach, however, is that fish do not have a standard shape and thus the shape specification is limited to classifying or identifying fish having the same or a very similar shape.
Still other systems classify images or video frames by using image statistics including color and texture. The difficulty with these systems is that for a given query image, even though the images located by the system may have the same color, textural, or other statistical properties as the example image, the images may not be part of the same class as the query image. That is, if the query image belongs to the class of images identified as human faces, then systems which classify images or video frames based image statistics including color and texture may return images which fall within the desired color and texture image statistics but which are not human faces.
It would thus be desirable to provide a system and technique which may be used in a general image search and retrieval system and which allows searching of a plurality of different types of images including but not limited to human or animal faces, fabric patterns, symbols, logos, art gallery and museum management, architectural image and design, interior design, remote sensing and management of earth resources, geographic information systems, scientific database management, weather forecasting, retailing, fabric and fashion design, trademark and copyright database management, law enforcement and criminal investigation, picture archiving, communication systems and inspection systems including circuit inspection systems. It would be particularly desirable to have the system be capable of automatically learning which factors are most important in searching for a particular image or for a particular type of image.